Pathfinder Society Paladin Spirit Bond, Mount or Weapon?

[Arillius]

I had an interesting idea for a character I'd like to make for my first Pathfinder Society game. Its a Straight paladin Half-orc, who uses spiked chain as a weapon from his alternate racial feature. The idea is that he was once a slave who managed to free himself but it almost cost him his life. A paladin happened upon his unconscious form and saved him, and since then the character would be using the form tools of oppression as a weapon of justice. I realize that it won't be for a while, but there is an option I'd want to take advantage of at creation depending on my choice for the characters Spirit bond.

From the sounds of it, the spirit weapon would be useful for some extra damage for the front liner, and would offer the use of its abilities for one, maybe two battles if they are close together. The paladin mount sound like once you summon it its there, but I couldn't find, perhaps a mistake on my part maybe, if there was a limit to its duration. It would offer its own advantages were I to go focus on mounted combat, and it sounds like I might be able to summon it at the beginning of the day and use it till the end maybe? That's my first question really. My second one is, how useful does the Spirit bonded weapon usually turn out to be? Is that extra damage from the flaming affect, or the added bonus of some of the other affects, or the straight up +'s really adding to a Paladin's ability to do damage?

Story wise I figured both would fit with my character very well to, so here, as in one or two other threads, I ask others for the opinion's of those with past experience or observations pertaining to either choice in hopes of finding the answer's I'm looking for, and perhaps some I wasn't but held no less need for.

[BobVosh]

Unless you are a small mount based build (which you aren't small, not sure about the other) it is generally better to just go with bonded weapon.
For my mounts I prefer to buy a giant eagle or regular horse.

[Ravens_cry]

I also go with the weapon, not only because most dungeons aren't made for large creatures, such as a medium paladins mount, but because paladins don't get the reductions in armour check penalty a Fighter gets, so Ride checks can be problematic.

[Arillius]

As to the size, I can see how that would be problematic. As to eagles, the ruling for pathfinder society is that your limited to animals with 4 legs as mounts for paladins, so it will most likely be a horse until around 7th level for him where I was thinking lion if it becomes an option.

As to the armor check penalty, there is an alternate paladin theme that gives up divine health in return for no armor check penalty being held against riders, so it really comes to size.

How often are PC's ever in a corridor or area that can fit a large creature? It might be a singularity amongst my groups, but it seems the closest we've come is spacious underground caverns or intricate sewer systems.